The present invention relates to contact carriers for relays and a method of producing such contact carriers as well as relays in which the contact carriers will be used.
In the majority of cases the contact carriers consist of springs formed as longish spring strips of mainly straight shape, but within the scope of the patent it is intended to include contact carriers in which the resilient capacity of the carriers takes second place and the magnetic properties of these are of greater interest.
One object of the present invention is to produce improvements as regards the construction of so-called reed relays. Such relays usually consist of a tube, which is usually sealed and evacuated or filled with an inert gas and contains spring strips inserted into this from each end of the tube with contact elements facing each other on the respective ends of the two springs, these last-mentioned ends being located at the middle of the tube so that the contact elements are at the said middle. For example, when it is a matter of a making contact, the contact elements (which usually consist of a point on one spring and a pad on the other spring) will be exactly opposite each other and are in the position of rest slightly separated from each other.
The springs consist of magnetic material, usually iron, with a low coercive force and high permeability and they are actuated by a winding arranged around the tube which, when supplied with current, produces magnetization of both springs by means of a magnetic flux which is usually switched on outside the tube by a yoke of magnetic material with low coercive force and high permeability passing between the ends of the tubes and located outside the winding arranged around the tube.
When the winding is supplied with current a magnetic flux will be set up through the springs principally in the lengthwise direction of the tube and the two springs will then be drawn towards each other and close the contacts, so that a circuit, in which the contact springs with pertaining contact elements are included, will likewise be made. By arranging a contact element on one spring located on a part on the other side of the opposing spring, a breaking of a circuit can be produced when the winding is supplied with current. By forming at least parts of the springs of permanently magnetic material and arranging these parts on the respective springs so that they will be brought very close to each other at the movement of the springs towards each other when the winding is supplied with current, it is possible to obtain a closure of the contacts that will remain even after the current feed to the winding has ceased. In such a case breaking is obtained by passing a current of short duration through the winding in the opposite direction.
As reed relays of various types are already well known to specialists in this field, it has been considered that the preceding account will be sufficient to obtain the background to the present invention.
As already stated, it is generally necessary for the said reed relays that the springs are magnetic. Springs of iron have been used for this, but it has been difficult to obtain a suitable compromise between magnetic properties and elastic properties etc. Springs of phosphor bronze with a layer of magnetic material mounted have also been used. Those have presented troublesome production problems and even difficulties as regards the magnetic properties of the said contact carriers in the form of springs made up of different materials.